Cardiac Embryology

Question 1

When does looping of the heart tube occur?

Answer 1

Week 4

Question 2

When does the heart tube begin to beat?

Answer 2

e21-22

Question 3

What provides the precursors for portions of both myocardium and endocardium?

Answer 3

Lateral Splanchnic mesoderm

Question 4

From where does the splanchnic mesoderm arrise?

Answer 4

-lateral plate mesoderm, forms along with somatic mesoderm

Question 5

What structures do blood vessels arise from?

Answer 5

Blood islands

Question 6

What is vasculogenesis?

Answer 6

the process of blood vessels arising from blood islands

Question 7

What is angiogenesis?

Answer 7

-the process by which new blood vessels sprout from existing ones

Question 8

What do cells from the first heart field form?

Answer 8

• cardiac crescent

- develops into linear heart tube and left ventricle

Question 9

What do cells from the second heart field form?

Answer 9

• outflow tracts
• right ventricle
• inflow tracts

Question 10

What brings the lateral endocardial tubes together in the developing embryo to form a single heart tube?

Answer 10

-Conformational changes due to rapid proliferation of neural tissue and closure of the foregut

Question 11

What separates the early myocardium and endocardium?

Answer 11

an accelular matrix secreted by the myocardium

Question 12

What embryonic structure becomes the aortic and pulmonary trunks?

Answer 12

The truncus Anteriosis

Question 13

What embryonic structure becomes the right ventricle?

Answer 13

The outlet

Question 14

What embryonic structure becomes the left ventricle?

Answer 14

The inlet

Question 15

What genes are key in precardiac cell differentiation?

Answer 15

Homeobox genes

Question 16

What is one of the first manifestiations of embryonic L-R Asymmetry?

Answer 16

-rightward looping of the heart tube

Question 17

What are basic helix-loop-helix transcription factors?

Answer 17

• bHLH

- are expressed to determine sidedness in the right and left ventricles

Question 18

Which transcription factor is expressed by the right ventricular segments?

Answer 18

HAND2

Question 19

Which transcription factor is expressed by the left ventricular segments?

Answer 19

HAND1

Question 20

What causes the ballooning of the cardiac ventricles?

Answer 20

-disproportionate growth on one side of the heart tube during looping

Question 21

What are the 4 steps in internal partitioning of the heart tube?

Answer 21

1. Atrial septation
2. Formation of endocaridal cushions and septation of AV canal
3. Ventricular septation
4. Septation of the truncus and conus arteriosus

Question 22

What first divides the atria?

Answer 22

Septum primum

Question 23

What covers the foramen secundum?

Answer 23

Septum secundum

Question 24

What forms the flap valve of the foramen ovale?

Answer 24

The overlapping of the septums primum and secundum

Question 25

When does atrial septation occur?

Answer 25

5 weeks gestation

Question 26

What does the foramen secundum become?

Answer 26

The interatrial foramen

Question 27

What does the smooth walled right atrium arise from?

Answer 27

the right sinus horn

Question 28

What does the smooth walled left atrium arise from?

Answer 28

incorporated common pulmonary vein

Question 29

What structure becomes the R and L atrial canals?

Answer 29

The common AV canal

Question 30

What growths form the common AV canal?

Answer 30

endocardial/mesenchymal cushion

Question 31

What does the first component of the ventricular septum arise from?

Answer 31

folding of the myocardium

Question 32

Where do the coronary arteries and cardiac veins arise from?

Answer 32

Pro-epicardium

Question 33

What differentiates/contributes to the SA node?

Answer 33

The sinuatrial ring

Question 34

What fuses to form the left and right atrioventricular canals?

Answer 34

The superior and inferior endocardial cushions

Question 35

What serves as an anchoring point for atrial and ventricular septa and AV valves?

Answer 35

The fused endocardial cushions

Question 36

How are the AV valves formed?

Answer 36

- Myocardium covered by cushion is "undermined" - Myocardium retracts and is replaced by dense connective tissue - Myocardium remaining nearer the apex forms the papillary muscle

Question 37

What forms the aortico-pulmonary septum?

Answer 37

Fusion of the endocardial ridges

Question 38

What is the aortico-pulmonary septum?

Answer 38

-divids the conus and truncus into an aortic and pulmonary channel

Question 39

What special cells contribute to endocardial cushion formation is the truncus arteriosus and conus cordis?

Answer 39

-Neural crest cells

Question 40

What forms the link between cardiac and craniofacial abnormalities?

Answer 40

-The abnormal migration, proliferation, or differentiation of neural crest cells

Question 41

What shunts oxygenated blood from the umbilical vein to bypass the liver?

Answer 41

Ductus venosus

Question 42

What results in pulmonary overcirculation?

Answer 42

- Ventricular septal defect | - Oxygenated blood from left ventricle is being pumped through the septum into the pulmonary circulation

Question 43

What is Tetralogy of Fallot?

Answer 43

- Tetralogy = 4 anomolies: - pulmonary stenosis - VS defect - Aortic override - Right ventricular hypertrophy

Question 44

What results in pulmonary stenosis and Aortic override?

Answer 44

The malalignment of the conoventricular septum

Question 45

What results in the ventricular septal defect in the tetralogy of fallot?

Answer 45

-The malalignment of the conoventricular septum causes it to not align with the interventricular ridge

Question 46

What results in the right ventricular hypertrophy in tetralogy of fallot?

Answer 46

-The stenosis of the pulmonary trunk causes the right ventricle to work harder, and get bigger

Question 47

What is aortic override?

Answer 47

- The aorta is positioned right over an ventricular septal defect, instead of in the left ventricle - happens in tetralogy of fallot

Question 48

What are the symptoms of tetralogy of fallot?

Answer 48

- decreased pulmonary blood flow - Desaturation at rest - progressive cyanosis without repair - "Blue" spells

Question 49

What happens to the ductus arteriosus in patients with tetralogy of fallot?

Answer 49

- It remains patent - blood flows from aorta, through ductus arteriosus, and into the pulmonary arteries - closes later on

Question 50

What is it called when the heart folds to the right instead of left?

Answer 50

Dextrocardia